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We studied a time history of X-ray spectral states of a black-hole candidate, 4U 1630-47, utilizing data from a number of monitoring observations with the Rossi X-Ray Timing Explorer over 1996--2004. These observations covered five outbursts of 4U 1630-47, and most of the data recorded typical features of the high/soft states. We found that the spectra in the high/soft states can be further classified into three states. The first spectral state is explained by a concept of the standard accretion disk picture. The second state appears in the so-called very high state, where a dominant hard component is seen and the disk radius apparently becomes too small. These phenomena are explained by the effect of inverse Compton scattering of disk photons, as shown by Kubota, Makishima, & Ebisawa (2001, ApJ, 560, L147) for GRO J1655-40. The third state is characterized in such a way that the disk luminosity varies in proportion to $T_{rm in}^2$, rather than $T_{rm in}^4$, where $T_{rm in}$ is the inner-disk temperature. This state is suggested to be an optically-thick and advection-dominated slim disk, as suggested by Kubota & Makishima (2004, ApJ, 601, 428) for XTE J1550-564. The second and third states appear, with good reproducibility, when $T_{rm in}$ and the total X-ray luminosity are higher than 1.2 keV and $sim2.5times10^{38}(D/10quad{rm kpc})^2l eft[cos{theta}/(1/sqrt{3})]^{-1}$ erg s$^{-1}$, respectively, where $D$ is the distance to the object and $theta$ is the inclination angle to the disk. The present results suggest that these three spectral states commonly appear among black-hole binaries under high accretion rates.
Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and hence the feedback they provide to their surroundings, depends strongly on their c
We re-analyzed SUZAKU data of the black hole candidate 4U 1630-472 being in the high/soft state. We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption lines can be satisfactorily modeled by the spectrum from an accretion disk
Recent XMM-Newton observations of the black-hole candidate 4U 1630-47 during the 2012 outburst revealed three relativistically Doppler-shifted emission lines that were interpreted as arising from baryonic matter in the jet of this source. Here we rea
We present the analysis of X-ray observations of the black hole binary 4U~1630$-$47 using relativistic reflection spectroscopy. We use archival data from the RXTE, Swift, and NuSTAR observatories, taken during different outbursts of the source betwee
We report on the analysis of the data collected by Swift, INTEGRAL and RXTE of the Black Hole Candidate (BHC) 4U 1630-47 during 3 consecutive outbursts occurred in 2006, 2008 and 2010, respectively. We show that, although a similar spectral and tempo